U.S. patent number 9,415,793 [Application Number 14/895,407] was granted by the patent office on 2016-08-16 for steering apparatus.
This patent grant is currently assigned to JTEKT CORPORATION. The grantee listed for this patent is JTEKT CORPORATION. Invention is credited to Tatsuro Kubota, Masayuki Nagaoka, Ryota Okano, Tomonori Sugiura, Eiji Tanaka, Yoshihito Yoshihara.
United States Patent |
9,415,793 |
Kubota , et al. |
August 16, 2016 |
Steering apparatus
Abstract
A steering apparatus includes a first member which rotates
together with an operation lever which is operated to rotate and a
third member which is supported rotatably via a friction reducing
mechanism by a second member which is restricted from rotating. A
cam mechanism which brings a fixed side plate into press contact
with a column side plate includes an axially facing surface which
is provided on the first member and on which a cam surface is
formed, an axially facing surface which is provided on the third
member, rolling elements which are interposed between both the
axially facing surfaces, and a retainer which holds the rolling
elements and which is restricted from rotating by the second
member.
Inventors: |
Kubota; Tatsuro (Shiki,
JP), Yoshihara; Yoshihito (Kashihara, JP),
Tanaka; Eiji (Kitakatsuragi-gun, JP), Sugiura;
Tomonori (Yamatokoriyama, JP), Okano; Ryota
(Hamamatsu, JP), Nagaoka; Masayuki (Kashiba,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
JTEKT CORPORATION |
Osaka-shi, Osaka |
N/A |
JP |
|
|
Assignee: |
JTEKT CORPORATION (Osaka-shi,
JP)
|
Family
ID: |
52143857 |
Appl.
No.: |
14/895,407 |
Filed: |
July 4, 2014 |
PCT
Filed: |
July 04, 2014 |
PCT No.: |
PCT/JP2014/067877 |
371(c)(1),(2),(4) Date: |
December 02, 2015 |
PCT
Pub. No.: |
WO2015/002288 |
PCT
Pub. Date: |
January 08, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160107676 A1 |
Apr 21, 2016 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 5, 2013 [JP] |
|
|
2013-141989 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B62D
1/184 (20130101) |
Current International
Class: |
B62D
1/184 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2007091210 |
|
Apr 2007 |
|
JP |
|
2010528935 |
|
Aug 2010 |
|
JP |
|
2004089722 |
|
Oct 2004 |
|
WO |
|
Other References
Sep. 22, 2014 International Search Report issued in International
Patent Application No. PCT/JP2014/067877. cited by applicant .
Jan. 5, 2016 International Preliminary Report on Patentability
issued in International Patent Application No. PCT/JP2014/067877.
cited by applicant .
May 18, 2016 Search Report issued in European Patent Application
No. 14820277.3. cited by applicant.
|
Primary Examiner: Condra; Darlene
Attorney, Agent or Firm: Oliff PLC
Claims
The invention claimed is:
1. A steering apparatus comprising: a fixed side plate which is
fixed to a body; a column side plate which is fixed to a steering
column which supports a steering shaft rotatably; a fastening shaft
which is inserted through fastening shaft insertion slots which are
respectively provided in the fixed side plate and the column side
plate; an operation lever which is operated to rotate about a
center axis of the fastening shaft; a first member which is
supported by the fastening shaft and which rotates about the center
axis together with the operation lever; a second member which is
supported by the fastening shaft and which is restricted from
rotating by the fastening shaft insertion slots; a third member
which is supported by the fastening shaft and which is interposed
between the first member and the second member; a friction reducing
mechanism which is interposed between the second member and the
third member and which thrust supports the third member so that the
third member rotates relative to the second member; and a cam
mechanism which attains locking by fastening the fixed side plate
to the column side plate and which includes a pair of axially
facing surfaces which are provided on the first member and the
third member and which face each other in an axial direction of the
fastening shaft, a cam surface which is formed on an axially facing
surface of the first member, a plurality of rolling elements which
roll between both axially facing surfaces in association with a
relative rotation of the first member and the third member, and a
retainer which holds the rolling elements and which is restricted
from rotating about the center axis by the second member, wherein
the friction reducing mechanism functions to make a rotating
resistance of the third member relative to the second member
smaller than a reaction force which the third member receives as a
result of a rolling resistance of the rolling elements.
2. The steering apparatus according to claim 1, wherein the
friction reducing mechanism is a thrust bearing.
3. The steering apparatus according to claim 1, wherein the
friction reducing mechanism is a lubricant.
4. The steering apparatus according to claim 1, wherein the
friction reducing mechanism is a coating layer having a low
friction property.
5. A steering apparatus comprising: a fixed side plate which is
fixed to a body; a column side plate which is fixed to a steering
column which supports a steering shaft rotatably; a fastening shaft
which is inserted through fastening shaft insertion slots which are
respectively provided in the fixed side plate and the column side
plate; an operation lever which is operated to rotate about a
center axis of the fastening shaft; a first member which is
supported by the fastening shaft and which rotates about the center
axis together with the operation lever; a second member which is
supported by the fastening shaft and which is restricted from
rotating by the fastening shaft insertion slots; a third member
which is supported by the fastening shaft and which is interposed
between the first member and the second member; a friction reducing
mechanism which is interposed between the first member and the
third member and which thrust supports one of the first member and
the third member so that the third member rotates relative to the
other; and a cam mechanism which attains locking by fastening the
fixed side plates to the column side plates and which includes a
pair of axially facing surfaces which are provided on the second
member and the third member and which face each other in an axial
direction of the fastening shaft, a cam surface which is formed on
an axially facing surface of the second member, a plurality of
rolling elements which roll between both axially facing surfaces in
association with a relative rotation of the second member and the
third member, and a retainer which holds the rolling elements and
which rotates together with the first member, wherein the friction
reducing mechanism functions to make a relative rotating resistance
between the first member and the third member smaller than a
reaction force which the third member receives as a result of a
rolling resistance of the rolling elements.
6. The steering apparatus according to claim 5, wherein the
friction reducing mechanism is a thrust bearing.
7. The steering apparatus according to claim 5, wherein the
friction reducing mechanism is a lubricant.
8. The steering apparatus according to claim 5, wherein the
friction reducing mechanism is a coating layer having a low
friction property.
Description
TECHNICAL FIELD
The present invention relates to a steering apparatus.
BACKGROUND ART
There is a position adjustable steering apparatus in which the
position of a steering wheel can be changed according to the build
or driving posture of a driver.
For example, in Patent Literature 1, after the position of a
steering wheel is adjusted, an operation lever is operated to
rotate so that a movable cam rotates relative to a fixed cam.
The movable cam which rotates moves balls on a spiral fixed rolling
path on the fixed cam and a spiral movable rolling path on the
movable cam to move the fixed cam in an axial direction.
This fastens together side plates fixed to the body and slide
plates fixed to the steering column to attain the locking of the
steering wheel in a desired position.
CITATION LIST
Patent Literature
[Patent Literature 1] JP-A-2010-528935
SUMMARY OF THE INVENTION
Technical Problem
However, although the balls roll relative to either of the fixed
cam and the movable cam, there are fears that the balls slip
relative to the other.
As this occurs, the operating effort to operate the operation lever
has to be increased.
Then, an object of the invention is to provide a steering apparatus
which can reduce the operating effort to operate an operation
lever.
Solution to Problem
With a view to achieving the object, an invention provides a
steering apparatus (1) comprising:
a fixed side plate (26, 27) which is fixed to a body (14);
a column side plate (23, 24) which is fixed to a steering column
(8) which supports a steering shaft (4) rotatably;
a fastening shaft (35) which is inserted through fastening shaft
insertion slots (34, 33) which are respectively provided in the
fixed side plate and the column side plate;
an operation lever (20) which is operated to rotate about a center
axis (C1) of the fastening shaft;
a first member (37) which is supported by the fastening shaft and
which rotates about the center axis together with the operation
lever;
a second member (38) which is supported by the fastening shaft and
which is restricted from rotating by the fastening shaft insertion
slots;
a third member (70) which is supported by the fastening shaft and
which is interposed between the first member and the second
member;
a friction reducing mechanism (80; LUB; CTL) which is interposed
between the second member and the third member and which thrust
supports the third member so that the third member rotates relative
to the second member; and
a cam mechanism (40) which attains locking by fastening the fixed
side plates to the column side plates and which includes a pair of
axially facing surfaces (37a, 70a) which are provided on the first
member and the third member and which face each other in an axial
direction (Y1) of the fastening shaft, a cam surface (44) which is
formed on the axially facing surface of the first member, a
plurality of rolling elements (41) which roll between both the
axially facing surfaces in association with a relative rotation of
the first member and the third member, and a retainer (42) which
holds the rolling elements and which is restricted from rotating
about the center axis by the second member,
wherein the friction reducing mechanism functions to make a
rotating resistance of the third member relative to the second
member smaller than a reaction force which the third member
receives as a result of a rolling resistance of the rolling
elements.
An invention provides a steering apparatus (1) comprising:
a fixed side plate (26, 27) which is fixed to a body (14);
a column side plates (23, 24) which is fixed to a steering column
(8) which supports a steering shaft (4) rotatably;
a fastening shaft (35) which is inserted through fastening shaft
insertion slots (34, 33) which are respectively provided in the
fixed side plate and the column side plate;
an operation lever (20) which is operated to rotate about a center
axis (C1) of the fastening shaft;
a first member (37P) which is supported by the fastening shaft and
which rotates about the center axis together with the operation
lever;
a second member (38P) which is supported by the fastening shaft and
which is restricted from rotating by the fastening shaft insertion
slots;
a third member (70P) which is supported by the fastening shaft and
which is interposed between the first member and the second
member;
a friction reducing mechanism (80; LUB; CTL) which is interposed
between the first member and the third member and which thrust
supports one of the first member and the third member so that the
third member rotates relative to the other; and
a cam mechanism (40P) which attains locking by fastening the fixed
side plates to the column side plates and which includes a pair of
axially facing surfaces (48Pb, 70a) which are provided on the
second member and the third member and which face each other in an
axial direction of the fastening shaft, a cam surface (44P) which
is formed on the axially facing surface of the second member, a
plurality of rolling elements (41) which roll between both the
axially facing surfaces in association with a relative rotation of
the second member and the third member, and a retainer (42) which
holds the rolling elements and which rotates together with the
first member,
wherein the friction reducing mechanism functions to make a
relative rotating resistance between the first member and the third
member smaller than a reaction force which the third member
receives as a result of a rolling resistance of the rolling
elements.
The parenthesized numerals denote corresponding constituent
elements or the like in embodiments which will be described later,
which does not, of course, mean that the invention is to be limited
to those embodiments.
Hereinafter, this will be true in this clause.
As will be described, the friction reducing mechanism may be a
thrust bearing (80).
As will be described, the friction reducing mechanism may be a
lubricant (LUB).
As will be described, the friction reducing mechanism may be a
coating layer (CTL) of a low friction material.
Advantageous Effect of the Invention
According to the invention, the retainer which holds the rolling
elements is restricted from rotating about the center axis of the
fastening shaft. Additionally, the friction reducing mechanism
functions to make the rotating resistance of the third member
relative to the second member smaller than the reaction force which
the third member receives as a result of the rolling resistance of
the rolling elements.
Consequently, when the operation lever is rotated, the first member
rotates together with the operation lever, and the rolling elements
roll on the cam surface of the first member, while the third member
which is supported rotatably via the friction reducing mechanism by
the second member which is restricted from rotating rotates in an
opposite direction to the rotating direction of the first member,
whereby the rolling elements are allowed to roll on the first
member and the third member in an ensured fashion.
As a result, the operating effort to operate the operation lever
can be reduced.
According to the invention, the retainer which holds the rolling
elements rotates together with the first member, and the rolling
elements roll on the cam surface of the second member.
Additionally, the friction reducing mechanism functions to make the
rolling resistance of the third member relative to the first member
smaller than the reaction force which the third member receives as
a result of the rolling resistance of the rolling elements.
Consequently, when the operation lever is rotated, the first member
rotates together with the operation lever, while the friction
reducing mechanism which is interposed between the first member and
the third member permits the relative rotation between the first
member and the third member, whereby the rolling elements are
allowed to roll on the first member and the third member in an
ensured fashion.
As a result, the operating effort to operate the operation lever
can be reduced.
According to the invention, the friction resistance can be reduced
remarkably by the thrust bearing which functions as the friction
reducing mechanism.
According to the invention, the friction resistance can be reduced
remarkably by the lubricant which functions as the friction
reducing mechanism.
According to the invention, the friction resistance can be reduced
remarkably by the coating layer of the low friction material which
functions as the friction reducing mechanism.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic diagram showing schematically the
configuration of a steering apparatus of a first embodiment of the
invention.
FIG. 2 is a sectional view illustrating the steering apparatus
which is taken along a line II-II in FIG. 1.
FIG. 3 is an exploded perspective view of the steering apparatus of
the first embodiment.
FIG. 4 is an enlarged sectional view of a fastening mechanism of
the first embodiment and the periphery thereof, which corresponds
to an enlarged view of part of FIG. 2.
FIG. 5 is a view resulting when an inner surface of a first member
of the first embodiment which functions as an axially facing
surface is seen from a front thereof.
FIG. 6 is an axial sectional view of the first member of the first
embodiment which shows a section taken along a line VI-VI in FIG.
5.
FIG. 7 is a sectional view of a holding groove of the first member
of the first embodiment, which shows an outline of a cam
surface.
FIG. 8 is a view resulting when an outer surface of a second member
of the first embodiment which functions as an axially facing
surface is seen from a front thereof.
FIG. 9 is a sectional view of the second member, which shows a
section taken along a line IX-IX in FIG. 8.
FIG. 10 is a front view of a third member of the first
embodiment.
FIG. 11 is a sectional view of the third member of the first
embodiment.
FIG. 12 is a sectional view of a thrust bearing of the first
embodiment.
FIG. 13 is a front view of a retainer of the first embodiment.
FIG. 14 is a sectional view of the retainer shown in FIG. 13, which
shows a section taken along a line XIV-XIV in FIG. 13.
FIG. 15 is a schematic sectional view of a cam mechanism of the
first embodiment.
FIG. 16 is a schematic view of a first stopper and a second stopper
which control a maximum value of a relative rotating amount of the
first member and the second member in the first embodiment.
FIG. 17 is a schematic view of the first member and the retainer of
the first embodiment, which shows a state in which when locking is
attained by the cam mechanism, a projecting portion (an engaging
portion) of the retainer fits in a recess portion (an engaged
portion) of the first member to thereby restrict the relative
rotation of the first member and the second member.
FIG. 18 is an enlarged sectional view of a fastening mechanism of a
second embodiment of the invention and the periphery thereof, which
shows an example in which a lubricant is used as a friction
reducing mechanism.
FIG. 19 is an enlarged sectional view of a fastening mechanism of a
third embodiment of the invention and the periphery thereof, which
shows an example in which a coating layer of a low friction
material is used as a friction reducing mechanism.
FIG. 20 is a sectional view of a holding groove of a first member
of a fourth embodiment, which shows an outline of a cam
surface.
FIG. 21 is an enlarged sectional view of a fastening mechanism of a
fifth embodiment and the periphery thereof.
DESCRIPTION OF EMBODIMENT
Hereinafter, referring to the drawings, embodiments of the
invention will be described specifically.
FIG. 1 is a schematic diagram showing schematically the
configuration of a position adjustable steering apparatus 1 of a
first embodiment of the invention.
Referring to FIG. 1, the steering apparatus 1 includes a steering
member 2 such as a steering wheel and a steering mechanism 3 which
turns steered wheels (not shown) in association with the turning of
the steering member 2.
A rack-and-pinion mechanism, for example, is used as the steering
mechanism 3.
The steering member 2 and the steering mechanism 3 are mechanically
connected together via a steering shaft 4 as a steering shaft, an
intermediate shaft 5 and the like.
The rotation of the steering member 2 is transmitted to the
steering mechanism 3 via the steering shaft 4, the intermediate
shaft 5 and the like.
The rotation transmitted to the steering mechanism 3 is converted
to an axial motion of a rack shaft, not shown.
This turns the steered wheels.
The steering shaft 4 has a tubular upper shaft 6 and a lower shaft
7 which are fitted together through spline fitting or serration
fitting, for example, so as to slide relatively.
The steering member 2 is connected to one end of the upper shaft
6.
The steering shaft 4 can extend and contract in an axial direction
X1 thereof.
The steering shaft 4 is inserted through a tubular steering column
8 and is supported via a plurality of bearings 9, 10 by the
steering column 8 so as to rotate therein.
The steering column 8 has an outer tube 11 which functions as an
upper tube and an inner tube 12 which functions as a lower
tube.
Both the tubes 11, 12 are fitted together so as to slide relatively
in their axial direction.
This allows the steering column 8 to extend and contract in its
axial direction, which enables the steering column 8 to execute a
telescopic adjustment which will be described later.
The outer tube 11 supports the upper shaft 6 rotatably via the
bearing 9.
Additionally, the outer tube 11 is connected to upper shaft 6 via
the bearing 9 so as to move together therewith in the axial
direction X1 of the steering shaft 4.
A lower column bracket 13 is fixed to an outer circumference of the
inner tube 12.
The lower column bracket 13 is supported rotatably on a lower fixed
bracket 15 which is fixed to the body 14 via a tilt center shaft
16.
The steering column 8 and the steering shaft 4 can rotate about the
tilt center shaft 16.
The steering member 2 can adjust its position in a height direction
by rotating the steering shaft 4 and the steering column 8 about
the tilt center shaft 16 (a so-called tilt adjustment).
Additionally, the steering member 2 can adjust its position in a
front-to-rear direction as well as the height direction by
extending and contracting the steering shaft 4 and the steering
column 8 in the axial direction X1 (the so-called telescopic
adjustment).
The steering apparatus 1 includes a fastening mechanism 17 which
attains a tilting lock and a telescoping lock so as to fix the
position of the steering member 2 whose height is now adjusted in
place.
Specifically, an upper column bracket 18 which functions as a
movable bracket is fixed to the outer tube 11.
The tilting lock and the telescoping lock are attained by
connecting the upper column bracket 18 to an upper fixed bracket 19
which is fixed to the body 14 by the fastening mechanism 17.
As a result, the position of the steering column 8 is fixed in
place relative to the body 14, whereby the position of the steering
member 2 is fixed in place.
Additionally, the fastening mechanism 17 functions to suppress
shakiness produced between both the tubes 11, 12 in which the
telescoping lock has been attained.
Specifically, the fastening mechanism 17 includes a sleeve 21 which
rotates as the operation lever 20 is operated to rotate and a
pressing portion 22 which is made up of a cam-shaped projection and
which is provided on an outer circumference of the sleeve 21 so as
to rotate together therewith.
The pressing portion 22 pressing the inner tube 12 upwards as a
result of the sleeve 21 rotating by operating the operation lever
20.
This causes the inner tube 12 to be pressed against the outer tube
11 in a radial direction so as to suppress the radial shakiness of
the inner tube 12 relative to the outer tube 11.
FIG. 2 is a sectional view illustrating the steering apparatus 1
which is taken along a line II-II in FIG. 1.
Referring to FIG. 2, the upper column bracket 18 is a groove-like
member which opens upwards and is formed symmetric laterally.
Namely, the upper column bracket 18 includes a pair of column side
plates 23, 24 which are fixed individually to an outer
circumference of the outer tube 11 at one end thereof and a
connection plate 25 which connects the pair of column side plates
23, 24 at the other end thereof.
The upper fixed bracket 19 is a groove-like member as a whole which
opens downwards and is formed symmetric laterally.
Namely, the upper fixed bracket 19 includes a pair of fixed side
plates 26, 27 which face each other in a left-to-right direction, a
connection plate 28 which connects the pair of fixed side plates
26, 27 at upper ends thereof, and a plate-shaped mounting stay 29
which is fixed to an upper surface of the connection plate 28 and
which extends generally in the left-to-right direction.
In FIG. 2, the steering shaft 4, the steering column 8 and the
upper column bracket 18 are disposed between the pair of fixed side
plates 26, 27 of the upper fixed bracket 19.
The upper fixed bracket 19 is fixed to the body 14 via a pair of
mount members 30 which are connected to the mount stay 29.
The mount members 30 and the mount stay 29 are connected together
with synthetic resin pins 31 which penetrate the mount stay 29 in
an up-to-down direction and which function as breakable connecting
members. Then, the mount members 30 are fixed to the body 14 with
fixing bolts 32.
Outer surfaces of the column side plates 23, 24 of the upper column
bracket 18 extend to follow inner surfaces of the corresponding
fixed side plates 26, 27 of the upper fixed bracket 19.
Horizontally elongated telescoping slots 33, which function as
fastening shaft insertion slots, are formed individually in the
pair of column side plates 23, 24 of the upper column bracket 18 so
as to extend in a direction which is at right angles to the surface
of a sheet of paper on which FIG. 2 is drawn (a direction
corresponding to the axial direction X1).
Vertically elongated tilting slots 34, which function as fastening
shaft insertion slots, are formed individually in the pair of fixed
side plates 26, 27 of the upper fixed bracket 19.
The fastening mechanism 17 includes a fastening shaft 35 which is
inserted through the tilting slots 34 in the fixed side plates 26,
27 and the telescoping slots 33 in the column side plates 23, 24,
the operation lever 20 which is connected to the fastening shaft 35
so as to rotate together with a head portion 351 which is provided
at one end 35a of the fastening shaft 35, a nut 36 which is screwed
on a thread portion which is formed at the other end 35b of the
fastening shaft 35, and a first interposed member 61 and a second
interposed member 62 which fit on a portion of a shaft portion 35c
which lies near the other end 35b of the fastening shaft 35 and
which are interposed between the nut 36 and the other fixed side
plate 27.
Additionally, the fastening mechanism 17 includes a first member 37
which fits on a portion of the shaft portion 35c which lies near
the one end 35a of the fastening shaft 35 so as not to move in the
axial direction and which rotates together with the operation lever
20, a second member 38 which fits on a portion of the shaft portion
35c which lies near the one end 35a of the fastening shaft 35 so as
not only to rotate relative to the fastening shaft 35 but also to
move in the axial direction and which is restricted from rotating
by the tilting slot 34 in the fixed side plate 26, a third member
70 which is interposed between the first member 37 and the second
member 38, a thrust bearing 80 which is interposed between the
second member 38 and the third member 70 and which functions as a
friction reducing mechanism, and a cam mechanism 40.
A thrust washer shown may be used as the thrust bearing 80.
Alternatively, a thrust ball bearing or a thrust roller bearing may
be used as the thrust bearing 80.
The cam mechanism 40 includes an axially facing surface 37a and an
axial end face 70a which are provided on the first member 37 and
the third member 70, respectively, and on at least one of which a
cam surface 44 is formed, a plurality of balls 41 as rolling
elements which roll between the axial end faces 37a, 70a, and a
retainer 42 which holds the balls 41 and which is restricted from
rotating about a center axis C1 by the second member 38.
The operation lever 20 is operated to rotate about the center axis
C1 of the fastening shaft 35.
The cam mechanism 40 functions as a motion converting mechanism
which converts the rotation of the first member 37 which is
triggered in association with the rotation of the operation lever
20 to an axial movement of the third member 70 so as to press the
fixed side plates 26, 27 individually against the corresponding
column side plates 23, 24.
Here, the cam mechanism means a mechanical interlocking mechanism
which imparts a predetermined motion (in this embodiment, a direct
motion in an axial direction Y1 of the fastening shaft 35) to a
driven portion (in this embodiment, corresponding to the third
member 70) according to a surface configuration of a cam (in this
embodiment, corresponding to the configuration of the cam surface
44).
As shown in FIG. 2, a spline (not shown) is provided on an inner
circumference 21a of the sleeve 21, and this spline is brought into
engagement with a spline 39 which is provided on an intermediate
portion of the fastening shaft 35 in the axial direction Y1
thereof.
The sleeve 21 and the fastening shaft 35 are spline joined
together, so that both the sleeve 21 and the fastening shaft 35
rotate together.
The pressing portion 22, which is made up of the cam-shaped
projection as described above, is provided on an outer
circumference 21b of the sleeve 21.
The pressing portion 22 passes through an insertion hole 11a which
is provided in the outer tube 11 so as to press against an outer
circumference 12a of the inner tube 12 as the sleeve 21
rotates.
As shown in FIG. 3, the first member 37 is made up of a holed
circular disk.
As shown in FIG. 5, a plurality of arc-shaped holding grooves 43
are formed on the axially facing surface 37a of the first member 37
so as to be spaced away from on another at equal intervals in a
circumferential direction Z1, and these holding grooves 43 hold
individually the balls 41.
As shown in FIGS. 5, 6 which is a sectional view taken along a line
VI-VI in FIGS. 5 and 7 which is a circumferential sectional view of
the first member 37, the cam surface 44 is formed on a bottom of
each of the holding grooves 43, and the cam surface 44 rises in the
axial direction Y1 as it extends in a circumferential direction
Z1.
As shown in FIGS. 4 and 6, a rectangular fitting projecting portion
45, for example, is provided on a rear surface of the axially
facing surface 37a of the first member 37.
As shown in FIG. 4, the fitting projecting portion 45 is fitted in
a fitting hole 46 in the operation lever 20, whereby the first
member 37 is connected to the operation lever 20 so as to rotate
together therewith.
As shown in FIG. 5, a plurality of first stoppers 47 are provided
at equal intervals in the circumferential direction Z1 on a
circumferential edge portion of the first member 37, and the first
stoppers 47 are each made up a plurality of arc-shaped projections
which project from the axially facing surface 37a towards the
second member 38.
Each first stopper 47 has a pair of circumferential end faces 47a
which function as stopper surfaces which face each other in the
circumferential direction Z1.
In the first stopper 47, as shown in FIG. 17, a recess portion 55,
which functions as an engaged portion, is formed on a radially
facing surface 47b which faces an outer circumference 42a (a
radially facing surface) of the retainer 42, and a projecting
portion 56 (refer to FIG. 13), which is provided on the outer
circumference 42a of the retainer 42 to function as an engaging
portion, is brought into engagement with the recess portion 55 when
the cam mechanism 40 locks the steering shaft 4.
As shown in FIGS. 4, 8 and 9 which is a sectional view taken along
a line IX-IX in FIG. 8, the second member 38 includes a holed
disc-shaped main body 48 which has an annular fastening surface 48a
which follows an outer surface of the fixed side plate 26 and a
flat, annular seat surface 48b which lies on an opposite side to a
side where the fastening surface 48a is provided to bear the thrust
bearing 80, a tubular fitting projecting portion 49 which is formed
on the fastening surface 48a and a circumferential side wall 50
which rises from a circumferential edge of the seat surface 48b in
an opposite direction (towards the first member 37) to the fitting
projecting portion 49.
As shown in FIG. 4, the fitting projecting portion 49 is fitted in
the tilting slot 34 in the fixed side plate 26 of the upper fixed
bracket 19 and the telescoping slot 33 in the column side plate 23
of the upper column bracket 18 so as to move along a direction in
which each of the grooves 34, 33 extends.
A pair of flat surfaces (not shown) which define a width across
flat therebetween, for example, are provided at a portion of the
fitting projecting portion 49 which fits in the tilting slot 34 in
the fixed side plate 26.
The second member 38 is restricted from rotating as a result of the
fitting projecting portion 49 fitting in the tilting slot 34.
As shown in FIGS. 8 and 9, a plurality of projections 51 are
provided on an axial end face of the circumferential side wall 50,
and these projections 51 are disposed at equal intervals in a
circumferential direction.
An engaging groove 53 is formed in each projection 51 so as to be
brought into engagement with a corresponding engaging projection 52
(refer to FIG. 13) which is provided on the outer circumference of
the retainer 42.
As shown in FIG. 17, the engaging projections 52 of the retainer 42
are brought into engagement with the corresponding engaging grooves
53 of the second member 38 which is restricted from rotating,
whereby the retainer 42 is restricted from rotating about the
center axis C1.
The projections 51 of the second member 38 function as second
stoppers which cooperate with the first stoppers 47 of the first
member 37 so as to control the rotation amount of the first member
37 relative to the second member 38.
Namely, as shown in FIGS. 16 and 17 which are both schematic views,
the first stoppers 47 and the second stoppers (the projections 51)
are disposed alternately in the circumferential direction Z1.
A circumferential end face 47a (a stopper surface) of the first
stopper 47 is brought into abutment with a circumferential end face
51a (a stopper surface) of the second stopper (the projection 51)
which faces the circumferential end face 47a, whereby a maximum
value of the rotation amount of the first member 37 relative to the
second member 38.
As shown in FIG. 13, the retainer 42 is made up of a holed circular
disc and is formed of a sheet of metal, for example, through
pressing.
As shown in FIGS. 13 and 14 which is a sectional view taken along a
line XIV-XIV in FIG. 13, the retainer 42 includes pockets 54 which
hold the corresponding balls 41 so as to roll.
One or a plurality of engaging projections 52 are provided on the
outer circumference 42a (the radially facing surface) of the
retainer 42 in such a way as to project outwards in the radial
direction R1 so as to be brought into engagement with the engaging
grooves 53 of the projections 51 of the second member 38.
The projecting portions 56 are provided on the outer circumference
42a of the retainer 42 so as to be brought into engagement with the
recess portions 55 of the first stoppers 47 of the first member 37
to thereby restrict the relative rotation of the first member 37
and the second member 38 when the locking is attained.
As shown in FIG. 13, the projecting portions 56 are provided on
flexible portions 57 which can elastically be displaced in the
radial direction.
Specifically, in the retainer 42, the flexible portions 57 are
formed between the projecting portions 56 and sectorial retainer's
material removed through holes 58, for example, by providing the
sectorial through holes 58 radially inwards of the projecting
portions 56.
When the cam mechanism 40 locks the steering shaft 4, as shown in
FIG. 17, the projecting portions 56 (the engaging portions) of the
retainer 42 are brought into engagement with the corresponding
recess portions 55 (the engaged portions) of the first stoppers 47
of the first member 37, whereby the first member 37 and the second
member 38 are restricted from rotating relatively.
The projecting portions 56 and the recess portions 55 make up a
relative rotation restricting mechanism 59.
As shown in FIGS. 10 and 11 which is a sectional view taken along a
line XI-XI in FIG. 10, the third member 70 is made up of a holed
circular disc.
The third member 70 has a pair of axial end faces 70a, 70b which
face each other in the axial direction.
As shown in FIG. 4, one axial end face 70a faces the axially facing
surface 37a of the first member 37, and the other axial end face
70b faces the thrust bearing 80.
An annular guide groove 71 is formed on the axial end face 70a so
as to guide the balls 41 which roll in the axial direction
(corresponding to the rotational direction Z1).
As shown in FIGS. 4 and 12, the thrust bearing 80 which functions
as the friction reducing mechanism is a thrust washer, for
example.
The thrust washer functioning as the thrust bearing 80 is made up
of a holed circular disc and has a pair of axial end faces 80a, 80b
each having an annular shape.
One axial end face 80a is brought into slidable contact with the
other axial end face 70b of the third member 70.
The other axial end face 80b is brought into slidable contact with
the seat surface 48b of the main body 48 of the second member
38.
At least the one axial end face 80a of the thrust bearing 80 is
formed of a low friction material such as a fluorine plastic, for
example.
However, both the axial end faces 80a, 80b may be formed of such a
low friction material.
The low friction material may be configured as a coating layer
which is coated on the predetermined axial end face. Alternatively,
the whole of the thrust bearing 80 may be formed of the low
friction material.
A thrust ball bearing or a thrust roller bearing, not shown, can be
used as the thrust bearing 80 in place of the thrust washer.
For example, a thrust needle roller bearing which is made up of a
retainer and rollers may be used or a thrust needle roller bearing
may be used in which rollers held by a retainer are interposed
between a pair of raceway plates which face each other in the axial
direction.
The thrust bearing 80, which is the friction reducing mechanism,
functions to make the rotating resistance of the third member 70
relative to the second member 38 smaller than a reaction force
which the third member 70 receives as a result of the rolling
resistance of the balls 41.
Referring to FIG. 2, again, the first interposed member 61 and the
second interposed member 62 are interposed between the nut 36 which
is screwed on the one end portion of the fastening shaft 35 and the
other fixed side plate 27 of the upper fixed bracket 19.
The first inter posed member 61 has a first portion 611 and a
second portion 612.
The first portion 611 of the first interposed member 61 follows an
outer surface of the other fixed side plate 27 of the upper fixed
bracket 19.
The second portion 612 of the first interposed member 61 is fitted
in the tilting slot 34 in the other fixed side plate 27 of the
upper fixed bracket 19 and the telescoping slot 33 in the other
column side plate 24 of the upper column bracket 18 so as to move
along the direction in which each of the grooves 34, 33
extends.
Additionally, a pair of flat surfaces which define a width across
flat therebetween, for example, are provided at a portion of the
second portion 612 which fits in the tilting slot 34 in the fixed
side plate 27, whereby the second portion 612 is restricted from
rotating by the tilting slot 34.
The second interposed member 62 includes a thrust washer 63 which
is interposed between the first portion 611 of the first interposed
member 61 and the nut 36 and a thrusting needle roller bearing 64
which is interposed between the thrust washer 63 and the first
portion 611 of the first interposed member 61.
The second interposed member 62 including the needle roller bearing
64 works to enable the nut 36 to rotate smoothly together with the
fastening shaft 35.
The first member 37 rotates relative to the second member 38 as the
operation lever 20 is rotated, whereby the second member 38 is
moved in the axial direction Y1 of the fastening shaft 35.
The pair of fixed side plates 26, 27 of the upper fixed bracket 19
are held to be fastened between the second member 38 which has so
moved and the first interposed member 61, as a result of which the
fixed side plates 26, 27 of the upper fixed bracket 19 fasten the
corresponding column side plates 23, 24 of the upper column bracket
18, whereby the tilting lock and the telescoping lock are
attained.
According to this embodiment, the retainer 42 which holds the balls
41 is restricted from rotating about the center axis C1 of the
fastening shaft 35. Additionally, the thrust bearing 80, which is
the friction reducing mechanism, functions to make the rotating
resistance of the third member 70 relative to the second member 38
smaller than the reaction force which the third member 70 receives
as a result of the rolling resistance of the balls 41.
Consequently, when the operation lever 20 is rotated, the first
member 37 rotates together with the operation lever 20, while the
third member 70 which is supported rotatably via the thrust bearing
80 by the second member 38 which is restricted from rotating
rotates in an opposite direction to the rotating direction of the
first member 37, whereby the balls 41 are allowed to roll on the
first member 37 and the third member 70 in an ensured fashion.
As a result, the operating effort to operate the operation lever 20
can be reduced.
The friction resistance of the third member 70 relative to the
second member 38 can be reduced remarkably by the thrust bearing 80
functioning as the friction reducing mechanism which is interposed
between the second member 38 and the third member 70.
Next, FIG. 18 shows a second embodiment of the invention.
The second embodiment shown in FIG. 18 differs from the first
embodiment shown in FIG. 4 mainly in the following point.
Namely, in the first embodiment, the thrust bearing 80 is used as
the friction reducing mechanism.
In contrast to the first embodiment, in the second embodiment, a
lubricant LUB is interposed between (an axial end face 70b of) a
third member 70 and (a seat surface 48b of a main body 48 of) a
second member 38 so as to be used as a friction reducing
mechanism.
A solid lubricant (for example, PTFE) is secured to at least one of
(the axial end face 70b of) the third member 70 and (the seat
surface 48b of the main body 48 of) the second member 38 so as to
work as the lubricant LUB in addition to grease.
Like reference numerals to those given to the constituent elements
of the first embodiment shown in FIG. 4 are given to like
constituent elements of the second embodiment shown in FIG. 18 to
those of the first embodiment shown in FIG. 4.
In the second embodiment, too, the same working effect as that of
the first embodiment can be provided, whereby the operating effort
to operate the operation lever 20 can be reduced.
Next, FIG. 19 shows a third embodiment of the invention.
The third embodiment shown in FIG. 19 differs from the first
embodiment shown in FIG. 4 mainly in the following point.
Namely, in the first embodiment, the thrust bearing 80 is used as
the friction reducing mechanism.
In contrast to the first embodiment, in the third embodiment, a
coating layer CTL of a low friction material such as a fluorine
plastic, for example, is coated on (an axial end face 70b of) a
third member 70 and (a seat surface 48b of a main body 48 of) a
second member 38 so as to be used as a friction reducing
mechanism.
Although not shown, the coating layer CTL of the low friction
material may be provided on both (the axial end face 70b of) the
third member 70 and (the seat surface 48b of the main body 48 of)
the second member 38.
Like reference numerals to those given to the constituent elements
of the first embodiment shown in FIG. 4 are given to like
constituent elements of the third embodiment shown in FIG. 19 to
those of the first embodiment shown in FIG. 4.
In the third embodiment, too, the same working effect as that of
the first embodiment can be provided, whereby the operating effort
to operate the operation lever 20 can be reduced.
The invention is not limited to the embodiments that have been
described heretofore. For example, in the embodiments, the engaging
portions are the projecting portions 56, and the engaged portions
are the recess portions 55. However, the invention is not limited
thereto. Either of the engaging portions and the engaged portions
should include projecting portions and the other should include
recess portions engaging with the projecting portions.
As this occurs, since the engaging portions and the engaged
portions fit in and on together or are brought into interlocking
engagement with each other, compared with a case where the engaging
portions and the engaged portions are brought into friction
engagement with each other, the holding of the locked state can be
ensured further.
Additionally, in the embodiments, the projecting portions 56 are
provided on the flexible portions 57 which can elastically be
deformed in the radial direction R1. However, the invention is not
limited thereto. At least either of the projecting portions and the
recess portions should be provided on the flexible portions which
can elastically be deformed in the radial direction.
As this occurs, the projecting portions and the recess portions are
brought into engagement with each other after the flexible portions
are once elastically deformed in the radial direction in
association with a relative rotation of at least one of the first
member 37 and the second member 38 and the member which rotates
relative to the one of the first and second members 37, 38, and
therefore, the interlocking engagement can smoothly be
executed.
Namely, in the event of the projecting portions or the recess
portions being provided on a retainer which is a member rotating
relatively, the flexible portions are provided on the retainer.
In the event of the flexible portions being provided on the
retainer, retainer's material removed through holes may be provided
in the retainer so as to form the flexible portions.
Additionally, in the event of the projecting portions or the recess
portions being provided on the first member or the second member
which is the member rotating relatively, the flexible portions are
provided on the first member or the second member.
In the event of the flexible portions being provided on the first
member or the second member, first member's or second member's
material removed through holes may be provided on the first member
or the second member on which the flexible members are
provided.
In the embodiments that have been described above, the engaging
portions (the projecting portions 56) are provided on the retainer
42, while the engaged portions (the recess portions 55) are
provided on the first member 37. However, the invention is not
limited thereto. Although not shown, the engaged portions (the
recess portions or the projecting portions) may be provided on the
second member 38 in place of the first member 37. Alternatively,
the engaged portions (the recess portions or the projecting
portions) may be provided on both the first member 37 and the
second member 38.
In the event of the engaged portions being provided on the first
member 37 and the second member 38, the engaged portions may be
provided on the first stoppers 47 and the second stoppers (the
projections 51).
In the embodiments that have been described above, the engaging
portions (the projecting portions 56) are provided on the retainer
42. However, the invention is not limited thereto, and hence, the
engaging portions and the engaged portions may not be provided on
the retainer 42.
For example, the engaging portions (the projecting portions or the
recess portions) which are provided on either of the first member
37 and the second member 38 and the engaged portions (the recess
portions or the projecting portions) which are provided on the
other of the first member 37 and the second member 38 may be
provided as a relative rotation restricting mechanism which
restricts the relative rotation of the first member 37 and the
second member 38 when the cam mechanism 40 locks the steering shaft
4.
In addition, as shown in a fourth embodiment depicted in FIG. 20,
in the midst of a ball 41 moving on a cam surface 44A to the left
(a locking side), the ball 41 may be made to be held in a locking
holding portion 44A2 which makes up a shallow trough after the ball
41 rides over a ridge portion 44A1 so as to enhance the locking
holding force.
FIG. 21 shows a fifth embodiment of the invention.
The fifth embodiment shown in FIG. 21 differs from the first
embodiment shown in FIG. 4, the second embodiment shown in FIG. 18
and the third embodiment shown in FIG. 19 mainly in the following
point.
Namely, in the first to third embodiments, in the fastening
mechanism 17, the retainer 42 of the cam mechanism 40 is restricted
from rotating by the second member 38 which cannot rotate, and the
friction reducing mechanism (the thrust bearing 80, the lubricant
LUB, the coating layer CTL) is interposed between the second member
38 and the third member 70.
Additionally, the cam surface 44 is provided on the first member
37.
In contrast to this, in the fifth embodiment shown in FIG. 21, in a
fastening mechanism 17P, a retainer 42 of a cam mechanism 40P
rotates together with a first member 37P which rotates together
with an operation lever 20, and a thrust bearing 80P (a friction
reducing mechanism) is interposed between the first member 37P and
a third member 70P.
A cam surface 44P (which may have the same configuration as that of
the cam surface 44A shown in FIG. 20) is provided on an axially
facing surface 48Pb of a main body 48P of the second member 38P
which lies opposite to a fastening surface 48Pa of the main body
48P.
Specifically, a circumferential side wall 50P is provided which
extends from an outer circumferential edge of the first member 37P
towards an opposite side (towards a second member 38P) to a side
where a fitting projecting portion 45 is provided.
An engaging projection 52 of the retainer 42 is in engagement with
an engaging groove 53P of the circumferential side wall 50P.
A flat and annular seat surface 37Pa of the first member 37P bears
the thrust bearing 80P (the friction reducing mechanism).
Like reference numerals to those given to the constituent elements
of the first embodiment shown in FIG. 4 are given to like
constituent elements of the fifth embodiment shown in FIG. 21 to
those of the first embodiment shown in FIG. 4.
According to the fifth embodiment, the retainer 42 which holds
balls 41 (rolling elements) rotates together with the first member
37P, and the balls 41 roll on the cam surface 44P of the second
member 38P.
The thrust bearing 80 (the friction reducing mechanism) functions
to make the rotating resistance of the third member 70P relative to
the first member 37P smaller than a reaction force which the third
member 70P receives as a result of the rolling resistance of the
balls 41.
Consequently, when the operation lever 20 is rotated, the first
member 37P rotates together with the operation lever 20, while the
thrust bearing 80P (the friction reducing mechanism) which is
interposed between the first member 37P and the third member 70P
permits the relative rotation between the first member 37P and the
third member 70P, whereby the balls 41 are allowed to roll on the
first member 37P and the third member 70P in an ensured
fashion.
As a result, the operating effort to operate the operation lever 20
can be reduced.
In the fifth embodiment, a lubricant or a coating layer of a low
friction material may be used as the friction reducing mechanism in
place of the thrust bearing 80P.
In addition, in this invention, various modifications can be made
without departing from the scope of claims of the invention, and
hence, for example, rollers can be used in place of the balls as
the rolling elements.
INDUSTRIAL APPLICABILITY
According to the invention, a steering apparatus is provided which
can reduce the operating effort to operate an operation lever.
REFERENCE SIGNS LIST
1 steering apparatus 2 steering member 3 steering mechanism 4
steering shaft (steering shaft) 8 steering column 11 outer tube 12
inner tube 14 body 17, 17P fastening mechanism 18 upper column
bracket 19 upper fixed bracket 20 operation lever 23, 24 column
side plates 26, 27 fixed side plates 33 telescoping slot (fastening
shaft insertion slot) 34 tilting slot (fastening shaft insertion
slot) 35 fastening shaft 37, 37P first member 37a axially facing
surface 38, 38P second member 40, 40P cam mechanism 41 ball
(rolling element) 42 retainer 43 holding groove 44, 44A, 44P cam
surface 48Pb axially facing surface 70, 70P third member 70a
axially facing surface 71 guide groove 80, 80P thrust bearing
(friction reducing mechanism) C1 center axis (of fastening shaft)
CTL coating layer LUB lubricant R1 radial direction X1 axial
direction (of steering shaft) Y1 axial direction (of fastening
shaft) Z1 circumferential direction
* * * * *